The citizens of the Bosporas were very rich; in early times the citizens, when they went to war, fought in full bronze hoplite regalia; later they would be an effective medium-heavy cavalry force, equipped much like Sarmatian nobles, though their equipment would be of higher quality.
Scythians would be employed as mercenaries, and an elite force of 'picked' Scythian cavalry is mentioned in at least one battle. They had a good amount of professional thureos-equipped infantry and cavalry, with Thorakites-style infantry become more prominent with Roman influence.
In essence, what Ludens said - cavalry was very important to their armies, with a substantial force of thureos-armed infantry and cavalry.
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